Do a Full Reset Amazon Echo Show 8
Echo Show giving you trouble? First, do the whole "unplug it and plug it back in" routine. You can also turn off an Echo Show by holding down the Mute button for a few seconds. (Power it back up again by holding down the Mute button again.)
If that doesn't help, nuke it, so to speak, by setting it back to the factory settings and starting fresh. Say "Alexa, go to settings" and tap Device Options > Reset to Factory Defaults. This kills all the settings you've put in place, from the name of your Echo Show to any linked accounts. You'll have to go through the setup all over again.
You can also do this in the Alexa mobile app. Go to the Settings > Device Settings > find your Echo Show and click the gear icon > Factory Reset.
Source : pcmag.com